Script to use from console

async_dns_f.py

@@ -0,0 +1,86 @@
+#!/usr/bin/python
+#
+# Peteris Krumins ([email protected])
+# http://www.catonmat.net  --  good coders code, great reuse
+#
+# Asynchronous DNS Resolution. v1.0.
+#
+# Read more about this code at:
+# http://www.catonmat.net/blog/asynchronous-dns-resolution
+#
+
+import adns
+from time import time
+import sys
+
+class AsyncResolver(object):
+    def __init__(self, hosts, intensity=100):
+        """
+        hosts: a list of hosts to resolve
+        intensity: how many hosts to resolve at once
+        """
+        self.hosts = hosts
+        self.intensity = intensity
+        self.adns = adns.init()
+
+    def resolve(self):
+        """ Resolves hosts and returns a dictionary of { 'host': 'ip' }. """
+        resolved_hosts = {}
+        active_queries = {}
+        host_queue = self.hosts[:]
+
+        def collect_results():
+            for query in self.adns.completed():
+                answer = query.check()
+                host = active_queries[query]
+                del active_queries[query]
+                if answer[0] == 0:
+                    ip = answer[3][0]
+                    resolved_hosts[host] = ip
+                elif answer[0] == 101: # CNAME
+                    query = self.adns.submit(answer[1], adns.rr.A)
+                    active_queries[query] = host
+                else:
+                    resolved_hosts[host] = None
+
+        def finished_resolving():
+            return len(resolved_hosts) == len(self.hosts)
+
+        while not finished_resolving():
+            while host_queue and len(active_queries) < self.intensity:
+                host = host_queue.pop()
+                query = self.adns.submit(host, adns.rr.A)
+                active_queries[query] = host
+            collect_results()
+
+        return resolved_hosts
+
+
+if __name__ == "__main__":
+    write_mode = 'a' #append
+
+    if len(sys.argv) != 3:
+        print 'Usage:', sys.argv[0], "input.txt output.txt"
+        exit()
+
+    in_file = sys.argv[1]
+    out_file = sys.argv[2]    
+
+    # read hosts from input file 
+    with open(in_file, 'r') as f:
+        hosts = [line.strip() for line in f.readlines()]    
+
+    ar = AsyncResolver(hosts, intensity=500)
+    start = time()    
+    resolved_hosts = ar.resolve()
+    end = time()    
+
+    print "It took %.2f seconds to resolve %d hosts." % (end-start, len(hosts))
+
+    # write results to output file
+    with open(out_file, write_mode) as f:
+        for key, item in resolved_hosts.items():
+            if item is None:
+                f.write("%s could not be resolved\n" % key)
+            else:
+                f.write("%s resolved to %s\n" %(key, item))